Detergent intermediate and process therefor

ABSTRACT

A detergent intermediate for use in phosphate-free detergent formulations is provided by absorbing a liquid surfactant onto a coarse light soda ash utilizing a pan pelletizer to effectuate absorption.

United States Patent 1 [111 3,764,541

Kaneko Oct. 9, 1973 [54] DETERGENT INTERMEDIATE AND 1,692,996 11/1928Richardson 252/DIG. 3

PROCESS THEREFOR Thomas M. Kaneko, Trenton, Mich.

[75] Inventor:

[73] Assignee: BASF Wyandotte Corporation,

Wyandotte, Michv [22] Filed: Dec. 23, 1971 [21] Appl. No.: 211,722

[52] US. Cl 252/89, 134/7, 252/DIG. l [51] Int. Cl ..Cl1d 3/02 [58]Field of Search 252/89, 92; 134/7 [56] References Cited UNITED STATESPATENTS 3,329,616 7/1967 Feierstein et a1. 252/DIG. 3

FOREIGN PATENTS OR APPLICATIONS 511,415 3/1955 Canada 252/89 PrimaryExaminer-William Schulz Attorney-Robert E. Dunn et a1.

[57] ABSTRACT A detergent intermediate for use in phosphate-freedetergent formulations is provided by absorbing a liquid surfactant ontoa coarse light soda ash utilizing a pan pelletizer to effectuateabsorption.

4 Claims, No Drawings DETERGENT INTERMEDIATE AND PROCESS THEREFORBACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention concerns phosphate-free detergents and ingredients therefor.More particularly, the present invention concerns a biodegradable,freeflowing detergent intermediate suitable for use in phosphate-freedetergents and which is prepared by absorbing, in a pan pelletizer, aliquid nonionic surfactant onto a carrier of coarse light soda ash.

2. Prior Art The great concern surrounding eutrophication and pollutionof our waterways, as a resultant from the use of phosphates indetergents and the like, has given rise to a groundswell of activity toprovide suitable replacements therefor.

To enable achievement of this end result the present invention, asabove-noted, provides a free-flowing biodegradable surfactant-loadedsoda ash intermediate for use in phosphate-free detergent formulations.

The absorption of surface active agents or surfactants onto inorganiccarriers has been known. See, for instance, US. Pat. Nos. 3,533,942,3,306,858 and 3,329,616. However, the present product and processtherefor is distinct from the art in that the amount of surfactantabsorbed on the soda ash has heretofore been unrealized. Moreover, theprocess utilized herein has not heretofore been disclosed or suggestedfor the preparation of such products.

Thus, it will become apparent to those skilled in the art that a majorstride in the preparation of phosphatefree detergents is provided by theinvention disclosed herein.

SUMMARY OF THE INVENTION In accordance with the present invention abiodegradable, free-flowing product is prepared in a pan pelletizer bythe absorption of a liquid, nonionic surfactant onto a base carrierconsisting essentially of a coarse light soda ash. The resulting,graulated product contains from about 15 to 30 percent by weight ofsurfactant.

For a more comprehensive discussion of the present invention, referenceis made to the following detailed description of the preferredembodiment and accompanying drawing which depicts the pan pelletizeremployed in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the presentinvention, a surfactant-loaded soda ash product useful as a detergentintermediate is prepared by absorbing onto coarse light soda ash aliquid nonionic surfactant utilizing a pan pelletizer to effectuateabsorption.

A pan pelletizer substantially comprises an open: ended cylinder or dischaving a cylindrical sidewall mounted on a motor-driven rotatable shaftdisposed at an inclined angle to the horizontal plane. As the discrotates, a solid feed is fed thereinto, the solid feed being sprayedwith a liquid absorbent as it is rotated. The construction of a panpelletizer is more completely shown in FIG. 5 on page 92 of ChemicalEngineering, Feb. 5, 1962.

It has been found that the use of a pan pelletizer gives a more uniform,free-flowing product than that obtained with other spray apparatus, suchas, ribbon blenders, screw feeders or the like. Moreover, by utilizingthe pan pelletizer there is substantially no breakdown of the soda ashparticles. Hence, the use of a pan pelletizer to the preparation of aproduct is considered to be of significant criticality.

The soda ash or sodium carbonate used herein must conform to certainstandards in order to be practicable within the scope of the instantinvention. It has been found that soda ash fines deleteriously affectthe properties of the resulting product, thus, it is essential thatfines be substantially eliminated as the surfactant carrier. Also, thegeneration of fines by attrition of the soda ash must be minimizedduring-mixing of the product. The soda ash which is employed herein is acoarse light soda ash.

As used herein and in the appended claims, the term coarse light sodaash means particles of sodium carbonate substantially one hundredpercent of which has a mesh size of 20 +100, U.S. Standard Sieve number,and preferably a mesh size of from l0 +80, U.S. Standard Sieve number.

Also, as used herein, the term absorption implies that the surfactant isdiffused into the crystal lattice structure of the soda ash as well assome of the surfactant remaining on the surface of the soda ash.

Within this mesh size range it is advantageous that the soda ashparticles have a distribution of about:

Mesh Size Soda Ash, by weight On 10 0.0-7.0

On 60 l0.075.0

On I00 0.0-6.0

On Pan 0.04.0

The nonionic surfactant which is absorbed onto the soda ash can beselected from any of the well-known liquid nonionic surfactants, such asalkoxylated alkyl phenols, Alkoxylated linear aliphatic alcohols, theconjugated alkylene oxide adducts of hydrophobic bases, and the like.

Suitable alkoxylated alkyl phenols are the ethylene oxide adducts ofalkyl phenols represented structurally RO- omm ,H

wherein R is an alkyl group having from 10 to 20 carbon atoms and .x isan integer sufficiently large to ensure that the ethylene oxide groupsconstitute from about 25 to 80 percent by weight of the surfactant.These surfactants are widely known and commercially available.

Another useful class of surfactants are the conjugated alkylene oxideadducts of hydrophobic bases which correspond to the formula:

wherein Y is the residue of an organic compound containing from two tosix carbon atoms and having x reactive hydrogens, x being at least two,a has a value such that the molecular weight of the polyoxypropylenebase is at least about 900 and not in excess of about 4000, and b has avalue such that the oxyethylene content of the molecule is from about 10to about 50 percent by weight. Compounds defined by Y include, forexample, propylene glycol, glycerine, pentaerythritol,trimethylolpropane, ethylene diamine, triethanolamine,triisopropanolamine, butylamine and the like. These surfactants are moreparticularly described in U.S. Pat. Nos. 2,674,619 and 2,979,528.

Preferred within this group of conjugated compounds are those whichcorrespond to the formula:

wherein a and b have the values described above and Y is propyleneglycol, and which are more particularly defined in the above-referred toU.S. Pat. No. 2,674,619.

Another useful class of nonionic surfactants are polyoxyalkylenecompounds having heteric polyoxyethylene chains, and which arerepresented structurally as:

wherein Y is the residue of an organic compound having x reactivehydrogens and up to six carbon atoms, P is a hydrophobic polyoxyalkylenechain having an oxygen/carbon atom ratio of not more than 0.40, themolecular weight of P and the value ofx being such that the molecule,excluding E, has a molecular weight of at least about 400 to 900 and upto about 25,000, and E is a hydrophilic polyoxyalkylene chain which (1)contains oxyethylene groups and at least percent by weight of highermolecular weight oxyalkylene groups having at least three carbon atomsin their structure, and (2) has an average oxygen/carbon atom ratio ofgreater than 0.40, E being present in the composition in an amountsufficient to constitute from about 5 to 90 percent by weight of thetotal composition. These surfactants are more particularly described inU.S. Pat. No. 3,101,374.

Still another useful class of liquid nonionic surfactants are thealkoxylates of linear aliphatic alcohols. These surfactants can begenerally designated as:

wherein R is the organic residue ofa linear aliphatic alcohol ormixtures thereof having from eight to 20 carbon atoms in the aliphaticportion, A represents oxyalkylene groups, and n is an integer such thatthe oxyalkylene groups constitute from 55 percent to 80 percent byweight of the compound. Generally, A represents oxyethylene groups,oxypropylene groups or mixtures thereof. These surfactants are generallyprepared either by using a random mixture of oxyalkylene groups or in'sequential addition thereof. When both oxyethylene groups andoxypropylene groups are employed they are present in a respective weightratio of from about 1:2 to 7:1. These surfactants are more particularlydescribed in U.S. Pat. Nos. 3,340,309, and 3,504,041 and Canada Pat. No.770,664.

Other useful surfactants include the propylene oxide adducts ofpolyoxyethylene glycol such as described in U.S. Pat. No. 3,036,118.

Although any conventional liquid nonionic surfactant can be employedherein, it is preferred to employ the two alkoxylates of linearaliphatic alcohols, since these are completely biodegradable. It shouldbe noted, also, that it is contemplated herein that surfactants whichare not conventionally liquid in nature can be 4 used herein if they areliquid at the temperatures employed in the present process which aremore fully defined hereinafter.

In preparing the detergent intermediate or builder of the presentinvention, the coarse light soda ash is loaded into the pan pelletizerand the liquid nonionic surfactant is sprayed thereonto. The surfactantis sprayed onto the soda ash at a temperature ranging from about 15 toC. and, preferably, at a temperature of from about 20 to 35 C. The sodaash is nominally at a temperature of about 15 to 95 C., and preferably,at about 20 to C., and in an amount ranging in parts by weight, fromabout 15 to 30 of .surfactant per to 70 of coarse light soda ash.

By operating within these parameters maximum absorption of soda ash isachieved. Neither the angle of inclination nor the speed at which theshaft rotates are critical to preparing the product.

The product obtained by the process of the present invention, is afree-flowing, biodegradable, detergent intermediate having from 15 to 30percent by weight of surfactant absorbed onto the coarse light soda ash.This is a distinct improvement over the prior art where such productscontain only minimal amounts of surfactants.

For a more complete understanding of the present invention, reference ismade to the following illustrative examples.

EXAMPLE I This example illustrates the preparation of a detergentintermediate in accordance with the present invention.

Using a three-foot inclined pan pelletizer rotating at 15 rpm and set atan angle of rotation of 225 from the horizontal plane about 870 lbs./hr.of a coarse light soda ash at a temperature of about 22 C. werecontinuously fed into the pelletizer. As the soda ash rotated, about 292lbs./hr. of a liquid nonionic surfactant at a temperature of about 22 C.was sprayed thereonto with a fan spray. After about 7.5 hours, 7,600lbs. of product were obtained. Random samplings of the resulting productshowed that an average of 25.4 percent, by weight, of surfactant hadbeen absorbed onto each particle of soda ash.

The product had an average flowability of about 63.4 percent asdetermined by a laboratory prepared test funnel that is fitted onto ahalf-gallon jar (the flowability is expressed as the ratio of the timein seconds required to empty the jar filled with a standard referencematerial, such as furnace grade sand, to the time required to empty thejar filled with the product being evaluated), and the following meshsize distribution:

U.S. Standard Sieve No. Amt. of Soda Ash,

following particle size distribution:

U.S. Standard Sieve No.

On Pan Amt. of Soda Ash, by weight The surfactant utilized herein wasthe condensation product of a mixture of C -C alcohols and a mixture ofethylene oxide and propylene oxide in a respective Weight ratio of about3:1, the resulting product containing about 60 percent by weight ofethylene oxide; about 20 percent by weight of propylene oxide, and about20 percent by weight of alcoholic residues. The starting mixture ofalcohols contained, by weight, about 20% C 30% C 30% C and 20% C fattyalcohols.

EXAMPLE 11 Following the procedure of Example I, substantially similarresults, Le. a free-flowing product containing 25 percent surfactant,were obtained utilizing the following surfactants:

1. the condensation product of a mixture of C C alcohols, as describedin Example 1 and a mixture of ethylene oxide and propylene oxide in arespective weight ratio of about 1.5: 1. The resulting productcontaining about 50 percent oxyethylene groups, about 30 percentoxypropylene groups and about 20 percent a1- coholic residues;

2. the condensation product of a mixture of C r-C alcohols, as describedin Example I, and a mixture of ethylene oxide and propylene oxide in arespective weight ratio of about 1:2, the resulting product containingabout 25 percent oxyethylene groups, about 50 percent oxypropylenegroups and about 25 percent alcoholic residues;

3. the ethylene oxide adduct of a 1750 molecular weight polyoxypropyleneglycol containing about 20 percent by weight of ethylene oxide;

4. a propylene oxide adduct of a 780 molecular weight polyoxyethyleneglycol containing about 75 percent by weight of propylene oxide, andmore particularly described in U.S. Pat. No. 3,036,118; and

5. a surfactant similar to Example 42 of US. Pat. No. 3,101,374 buthaving a total molecular weight of about 3,900 with the hydrophilicchain constituting about 30 percent of the total molecular weight of thesurfactant.

The percent flowabilities of the products produced, by loading 25percent of each surfactant onto the coarse light ash were as follows:

% Flowability 71.7 71.0 76.8 77.7 76.8

Surfactant The coarse light ash used in this example had the followingparticle size distribution:

Mesh Size On 20 3 On 60 69.6 On 80 22 On 100 3 On Pan 2 EXAMPLE IllIngredient Amount Detergent Intermediate 32 Sodium Metasilicate 15Sodium Sulfate 45 Sodium Gluconate 8 This composition was tested andcompared with a standard domestic detergent for foaming characteristicsusing a milk soil test and an egg soil test.

Predicated on the theorem that the number of revolutions of a dishwasherrotor arm is inversely proportional to the foam generated therein. Thetest employed was substantially as follows:

Into a domestic dishwasher, equipped with an electric counter whichcounts the revolutions of the rotor, maintained at the desiredtemperature is placed a watch glass containing 20 parts of detergent andeither 12 parts of dry powdered milk or 15 ml. of stirred raw whole egg,depending on the desired soil. As the door in the dishwasher is closed,the counter is turned on and a stop watch is commenced. The number ofrevolutions of the rotor arm is then recorded after the first minute ofoperation and after the second minute. The difference therebetween isthe number of revolutions for the second minute of operation. The samedetermination is made for the third and fourth minutes to determine thenumber of revolutions for the fourth minute of operation. The average ofthe two readings is utilized as the recorded value of RPMs.

The results of this test for the built detergent prepared from thepresent invention and the comparative detergent were as follows:

Average Rotor Arm Speed, RPM

It can be seen from the above that in all instances the detergentprepared from the detergent intermediate of the present inventionoutperformed the domestic product.

It should be further noted that soiled drinking glasses placedcontemporaneously in the dishwasher with the soiled watch glass havingthe detergent composition of the present invention placed thereonemerged from the dishwasher with no water streaks or spots.

Having thus described the invention, what it is desired to claim andsecure by Letters Patent is:

1. A process for the preparation of a detergent intermediate comprisingabsorbing onto a coarse light soda ash at a temperature of from 1595C,in a pan pelletizer a nonionic surfactant at a temperature of from 1565C, the soda ash having absorbed thereon from about 15 to 30 percent byweight of surfactant based on the weight of the intermediate.

2. The process of claim 1 wherein the soda ash has a mesh size of 20 US.Standard Sieve number.

3. The process of claim 2 wherein the soda ash has a US Standard Sievenumber mesh size of-lO +80.

4. The process of claim 1 wherein the surfactant is sprayed onto thesoda ash.

2. The process of claim 1 wherein the soda ash has a mesh size of -20+100 U.S. Standard Sieve number.
 3. The process of claim 2 wherein thesoda ash has a U.S. Standard Sieve number mesh size of -10 +80.
 4. Theprocess of claim 1 wherein the surfactant is sprayed onto the soda ash.